TY - JOUR
T1 - Trends and regional distributions of land and ocean carbon sinks
AU - Sarmiento, Jorge Louis
AU - Gloor, M.
AU - Gruber, N.
AU - Beaulieu, C.
AU - Jacobson, A. R.
AU - Fletcher, S. E.Mikaloff
AU - Pacala, Stephen Wilson
AU - Rodgers, K.
PY - 2010
Y1 - 2010
N2 - We show here an updated estimate of the net land carbon sink (NLS) as a function of time from 1960 to 2007 calculated from the difference between fossil fuel emissions, the observed atmospheric growth rate, and the ocean uptake obtained by recent ocean model simulations forced with reanalysis wind stress and heat and water fluxes. Except for interannual variability, the net land carbon sink appears to have been relatively constant at a mean value of -0.27 Pg C yr-1 between 1960 and 1988, at which time it increased abruptly by -0.88 (-0.77 to -1.04) Pg C yr-1 to a new relatively constant mean of -1.15 Pg C yr-1 between 1989 and 2003/7 (the sign convention is negative out of the atmosphere). This result is detectable at the 99% level using a t-test. The land use source (LU) is relatively constant over this entire time interval. While the LU estimate is highly uncertain, this does imply that most of the change in the net land carbon sink must be due to an abrupt increase in the land sink, LS Combining double low line NLS - LU, in response to some as yet unknown combination of biogeochemical and climate forcing. A regional synthesis and assessment of the land carbon sources and sinks over the post 1988/1989 period reveals broad agreement that the Northern Hemisphere land is a major sink of atmospheric CO2, but there remain major discrepancies with regard to the sign and magnitude of the net flux to and from tropical land.
AB - We show here an updated estimate of the net land carbon sink (NLS) as a function of time from 1960 to 2007 calculated from the difference between fossil fuel emissions, the observed atmospheric growth rate, and the ocean uptake obtained by recent ocean model simulations forced with reanalysis wind stress and heat and water fluxes. Except for interannual variability, the net land carbon sink appears to have been relatively constant at a mean value of -0.27 Pg C yr-1 between 1960 and 1988, at which time it increased abruptly by -0.88 (-0.77 to -1.04) Pg C yr-1 to a new relatively constant mean of -1.15 Pg C yr-1 between 1989 and 2003/7 (the sign convention is negative out of the atmosphere). This result is detectable at the 99% level using a t-test. The land use source (LU) is relatively constant over this entire time interval. While the LU estimate is highly uncertain, this does imply that most of the change in the net land carbon sink must be due to an abrupt increase in the land sink, LS Combining double low line NLS - LU, in response to some as yet unknown combination of biogeochemical and climate forcing. A regional synthesis and assessment of the land carbon sources and sinks over the post 1988/1989 period reveals broad agreement that the Northern Hemisphere land is a major sink of atmospheric CO2, but there remain major discrepancies with regard to the sign and magnitude of the net flux to and from tropical land.
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U2 - 10.5194/bg-7-2351-2010
DO - 10.5194/bg-7-2351-2010
M3 - Article
AN - SCOPUS:77955528140
SN - 1726-4170
VL - 7
SP - 2351
EP - 2367
JO - Biogeosciences
JF - Biogeosciences
IS - 8
ER -